Microelectromechanical sensors have been produced using manufacturing techniques developed in the microelectronics industry. More particularly, fluid property sensors such as pressure sensors have been implemented in Microelectromechanical Systems (MEMS) as discussed, for example, in U.S. Pat. No. 5,453,628 and U.S. Pat. No. 4,706,100. Conventional MEMS pressure sensors measure pressure-induced deflections in diaphragms using capacitance measurements, tunneling current measurements, resonant strain gauge measurements, and piezoresistance measurements. These conventional diaphragm based sensors typically respond to a difference in pressure on two sides of the diaphragm. Accordingly, a known pressure may need to be maintained on one side of the diaphragm.
Other MEMS pressure sensors may measure shifts in mechanical resonance frequencies or thermal conduction to the surrounding gas. Mechanical resonance sensors, however, may have high pressure limits as Q approaches 1. Thermal conduction sensors may have poor resolution at low pressures where conductive heat transfer may be on the order of radiative cooling.
Accordingly, there continues to exist a need in the art for improved microelectromechanical fluid property sensors.